Font issue in main menu


In Firefox I'm having a font issue:
I've played around in the web developer toolbar to see if I could quickly find a possible cause, sadly it didn't matter. The font rendered fine for me on the google page. I've checked if any extensions could be causing this, though this doesn't seem to be the case.

Browser version: 71.0 (64-bit)
OS: Windows 10

Font issue in main menu


I'm having the same issue. However it happens to me on Firefox (72) and (cough cough) Internet explorer (11)

Edit: It seems the issue is with the font Yanone Kaffeesatz, and its bold ´weight. I've been using firefox developer tool to mess a bit and removing the "bold" from font-weight on the style fa-font fixed the issue